Photomask layouts and methods of forming patterns using the same

ABSTRACT

A photomask layout includes: a substrate region; a lower stepped region at a region of the substrate region; and a pattern region at least partially crossing the lower stepped region and including at least one notch portion at an area overlapping the lower stepped region. A method of forming a pattern is also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/709,344, filed Sep. 19, 2017, which is a divisional of U.S. patentapplication Ser. No. 14/802,815, filed Jul. 17, 2015, now U.S. Pat. No.9,798,227 issued Oct. 24, 2017, which claims priority to Korean PatentApplication No. 10-2015-0017905, filed on Feb. 5, 2015 in the KoreanIntellectual Property Office (KIPO), the entire content of all of whichare incorporated herein by reference.

BACKGROUND 1. Field

Embodiments of the present invention relate to photomask layouts andmethods of forming patterns using the same. More particularly,embodiments of the present invention relate to photomask layouts for acircuit formation and methods of forming patterns using the same.

2. Description of the Related Art

A photolithography process may be implemented when, for example, forminga gate structure and a wiring of a semiconductor device, a circuit or athin film transistor (TFT) of a display device such as an organic lightemitting display (OLED) device and a liquid crystal display (LCD)device, etc.

In the photolithography process, a photomask layout in which a circuitpattern is designed may be prepared, and a photoresist layer may bepatterned using the photomask layout. A conductive layer may bepatterned using the resultant photoresist pattern to form thepredetermined circuit pattern.

A precise and fine construction of the photomask layout may be requiredin order to obtain the circuit pattern having desired width and pitch.

SUMMARY

According to an aspect of embodiments of the present invention, aphotomask layout has improved accuracy and/or precision.

According to another aspect of embodiments of the present invention, amethod of forming a pattern using the photomask layout has improvedaccuracy and/or precision.

According to one or more embodiments of the present invention, aphotomask layout includes: a substrate region; a lower stepped region ata region of the substrate region; and a pattern region at leastpartially crossing the lower stepped region and including at least onenotch portion at an area overlapping the lower stepped region.

In one or more embodiments, the at least one notch portion may bepositioned at a boundary area in which the pattern region overlaps thelower stepped region.

In one or more embodiments, the at least one notch portion may bepositioned at an intersection region of the lower stepped region and thepattern region.

In one or more embodiments, the at least one notch portion may bepositioned at at least one vertex of the intersection region.

In one or more embodiments, the pattern region may completely cross thelower stepped region, and the at least one notch portion may includefour notch portions positioned at the intersection region.

In one or more embodiments, the pattern region may partially cross thelower stepped region, and the at least one notch portion may include twonotch portions positioned at the intersection region.

In one or more embodiments, the pattern region may cross each of thelower stepped region and another lower stepped region, and the at leastone notch portion may be a number of notch portions that is a multipleof four.

In one or more embodiments, the lower stepped region may correspond toan active pattern or a lower wiring on a display substrate. The patternregion may correspond to an upper wiring on the active pattern or thelower wiring.

According to one or more embodiments of the present invention, a methodof forming a pattern includes: forming a lower stepped pattern on asubstrate; forming an upper pattern layer on the substrate, the upperpattern layer covering the lower stepped pattern; forming a photoresistlayer on the upper pattern layer; partially removing the photoresistlayer using a photomask to form a photoresist pattern, the photomaskincluding a light-shielding portion that at least partially crosses thelower stepped pattern and includes a recessed portion; and partiallyremoving the upper pattern layer using the photoresist pattern to forman upper pattern.

In one or more embodiments, an inclined region may be defined by asidewall of the lower stepped pattern, and the recessed portion may atleast partially overlap the inclined region.

In one or more embodiments, the recessed portion of the light-shieldingportion may be formed at an intersection region of the light-shieldingportion and the lower stepped pattern.

In one or more embodiments, the recessed portion of the light-shieldingportion may be formed at a vertex of the intersection region.

In one or more embodiments, the method further includes forming a lowerinsulation layer covering the lower stepped pattern on the substratebefore forming the upper pattern layer.

In one or more embodiments, the lower insulation layer may be partiallyetched to form a contact hole through which the lower stepped pattern isexposed. The upper pattern may fill the contact hole.

In one or more embodiments, the lower stepped pattern may be formed of aconductive material or a semiconductor material, and the upper patternlayer may be formed of a conductive material.

In one or more embodiments, the substrate may serve as a displaysubstrate of a display device. The lower stepped pattern may serve as anactive pattern or a signal pad of the display device. The upper patternmay serve as an upper wiring formed on the lower stepped pattern.

In one or more embodiments, the upper pattern may include a contactportion electrically connected to the lower stepped pattern.

In one or more embodiments, the photoresist pattern and the upperpattern may have a uniform width.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects and features of the present invention will be more clearlyunderstood from the following description of some example embodiments,taken in conjunction with the accompanying drawings. FIGS. 1 to 19represent some non-limiting, example embodiments as described herein:

FIG. 1 is a top plan view illustrating a photomask layout in accordancewith one or more embodiments of the present invention;

FIGS. 2 and 3 are top plan views illustrating photomask layouts inaccordance with one or more embodiments of the present invention;

FIGS. 4 to 10 are cross-sectional views and top plan views illustratinga method of forming a pattern in accordance with one or more embodimentsof the present invention;

FIGS. 11 and 12 are a cross-sectional view and a top plan view,respectively, illustrating a method of forming a pattern in accordancewith a comparative example; and

FIGS. 13 to 19 are cross-sectional views and top plan views illustratinga method of forming a pattern in accordance with one or more embodimentsof the present invention.

DETAILED DESCRIPTION

Various example embodiments will be described more fully hereinafterwith reference to the accompanying drawings, in which some exampleembodiments are shown. The present inventive concept may, however, beembodied in many different forms and should not be construed as limitedto the example embodiments set forth herein. Rather, these exampleembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the present inventiveconcept to those skilled in the art. In the drawings, the sizes andrelative sizes of layers and regions may be exaggerated for clarity.Like numerals refer to like elements throughout.

It will be understood that, although the terms “first,” “second,”“third,” etc. may be used herein to describe various elements, theseelements should not be limited by these terms. These terms are used todistinguish one element from another. Thus, a “first” element discussedbelow could be termed a “second” element without departing from theteachings of the present inventive concept. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that when an element is referred to as being“connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.).

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting of thepresent inventive concept. As used herein, the singular forms “a,” “an,”and “the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. It will be further understood thatthe terms “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this inventive concept belongs. Itwill be further understood that terms, such as those defined in commonlyused dictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

FIG. 1 is a top plan view illustrating a photomask layout in accordancewith one or more embodiments of the present invention.

Referring to FIG. 1, a photomask layout 100 may include a substrateregion 110, a lower stepped region 120, and a pattern region 130.

The substrate region 110 may correspond to, for example, a top surfaceof a substrate in a display device, such as an OLED device or an LCDdevice, for example.

Two directions substantially parallel to the top surface of thesubstrate and crossing each other are defined as a first direction and asecond direction. For example, the first and second directions may beperpendicular to each other. A direction indicated by an arrow and areverse direction thereof are considered as the same direction. Thedefinition of the directions may be applied throughout all of thedrawings.

The lower stepped region 120 indicated by a dashed line may correspondto a predetermined lower pattern formed on the top surface of thesubstrate. In one or more embodiments, the predetermined lower patternmay include an active pattern formed of a semiconductor material, or alower conductive pattern.

The lower stepped region 120 is illustrated as a rectangular shape inFIG. 1. However, the shape of the lower stepped region 120 may beproperly adjusted according to a construction of the predetermined lowerpattern.

The pattern region 130 may correspond to a pattern transferred from aphotolithography process using the photomask layout 100. In one or moreembodiments, the pattern formed from the pattern region 130 may includea circuit pattern such as source and drain wirings included in thedisplay device.

In one or more embodiments, the pattern region 130 may cross the lowerstepped region 120. For example, the pattern region 130 and the lowerstepped region 120 may extend in the second direction and the firstdirection, respectively.

The pattern region 130 may include at least one notch portion 140. Thenotch portion 140 may have a recess shape or a substantial recess shapeformed at the pattern region 130.

In one or more embodiments, the notch portion 140 may at least partiallyoverlap the lower stepped region 120. In one or more embodiments, thenotch portion 140 may partially overlap the lower stepped region 120,and a remaining area of the notch portion 140 may overlap the substrateregion 110.

The notch portion 140 may be formed at each boundary area in which thepattern region 130 and the lower stepped region 120 may cross eachother. As illustrated in FIG. 1, an intersection region 133 may bedefined by the pattern region 130 and the lower stepped region 120 asindicated by a dashed quadrangle. Four notch portions 140 may be formedat the intersection region 133. For example, the notch portion 140 maybe formed at a vertex of the intersection region 133.

FIGS. 2 and 3 are top plan views illustrating photomask layouts inaccordance with some example embodiments.

Referring to FIG. 2, a photomask layout 101 may include a plurality oflower stepped regions 123 and a plurality of pattern regions 135.

The plurality of the lower stepped regions 123 extending in the firstdirection may be arranged along the second direction. The plurality ofthe pattern regions 135 extending in the second direction may bearranged along the first direction.

The pattern region 135 may be superimposed over the plurality of thelower stepped regions 123. Accordingly, a plurality of intersectionregions may be defined from one of the pattern regions 135. As describedabove, a notch portion 145 may be formed at a boundary area in which thepattern region 135 and the lower stepped region 123 cross each other.Thus, in an implementation of FIG. 2, the number of the notch portions145 included in the one of the pattern regions 135 may be a multiple offour, e.g., eight of the notch portions 145, as illustrated in FIG. 2.

In one or more embodiments, the lower stepped region 123 may correspondto a lower wiring extending on a top surface of a substrate. The patternregion 135 may correspond to an upper wiring extending and beingsuperimposed on the lower wiring.

Referring to FIG. 3, a photomask layout 103 may include a first lowerstepped region 125 and a second lower stepped region 127. The first andsecond lower stepped regions 125 and 127 may have shapes and/ordimensions different from each other.

A pattern region 150 may extend in, for example, the second direction,and may overlap the first and second lower stepped regions 125 and 127.In one or more embodiments, the pattern region 150 may cross the firstlower stepped region 125, and may partially overlap the second lowerstepped region 127.

As illustrated with reference to FIGS. 1 and 2, the pattern region 150may include notch portions at boundary areas overlapping the lowerstepped regions 125 and 127.

As illustrated in FIG. 3, for example, four of first notch portions 160may be formed at an intersection region of the pattern region 150 andthe first lower stepped region 125. Two of second notch portions 165 maybe formed at an intersection region of the pattern region 150 and thesecond lower stepped region 127.

In one or more embodiments, the pattern region 150 may include a contactregion 155 defined by a portion of the pattern region 150 overlappingthe second lower stepped region 127. For example, the contact region 155may be transferred into a contact that may be in contact with a lowerpattern formed in the second lower stepped region 127.

In one or more embodiments, for example, a lower wiring of a displaydevice may be formed in the first lower stepped region 125. An activepattern including a semiconductor material such as amorphous silicon oran oxide semiconductor may be formed in the second lower stepped region127.

According to example embodiments as described above, the photomasklayout may include the notch portion in the pattern region. The notchportion may be formed at a boundary area with the lower stepped regiongenerating a stepped portion on a substrate. Thus, a spreading of aphotoresist material and a width increase of a target pattern due to adiffused reflection while performing an exposure process, which may becaused by the stepped portion, may be prevented or substantiallyprevented.

FIGS. 4 to 10 are cross-sectional views and top plan views illustratinga method of forming a pattern in accordance with one or more exampleembodiments. Specifically, FIGS. 4, 5, 7, and 9 are cross-sectionalviews illustrating the method. FIGS. 6, 8, and 10 are top plan viewsillustrating the method.

For example, FIGS. 4 to 10 illustrate a method of forming a patternutilizing the photomask layout illustrated with reference to FIG. 1, 2,or 3.

Referring to FIG. 4, a lower stepped pattern 210 and a lower insulationlayer 220 may be formed on a substrate 200.

The substrate 200 may be provided as a base substrate or a back-plane(BP) substrate of a display device, such as an OLED device or an LCDdevice. In one or more embodiments, a transparent insulation substratemay be used as the substrate 200. For example, the substrate 200 mayinclude a glass substrate, a transparent plastic substrate including,e.g., polyimide, polyethylene terephthalate (PET), or polyethylenenaphthalate (PEN), or a transparent metal oxide substrate.

In one or more example embodiments, a lower pattern layer may be formedon the substrate 200, and the lower pattern layer may be partiallyetched by a first photo process to form the lower stepped pattern 210. Aphotomask layout used in the first photo process may include a patternregion corresponding to the lower stepped region illustrated in FIG. 1,2, or 3.

In one or more example embodiments, the lower pattern layer may beformed of a conductive material including a metal such as tungsten,copper, aluminum, etc., or a metal nitride. In this case, the lowerstepped pattern 210 may serve as a lower wiring of the display device.

In one or more embodiments, the lower pattern layer may be formed of asilicon compound such as amorphous silicon, or an oxide semiconductorsuch as indium gallium zinc oxide (IGZO), indium tin zinc oxide (ITZO),etc. In this case, the lower stepped pattern 210 may serve as an activepattern of the display device.

The lower pattern layer may be formed by a chemical vapor deposition(CVD) process, a plasma enhanced chemical vapor deposition (PECVD)process, a high density plasma-chemical vapor deposition (HDP-CVD)process, a thermal evaporation process, a sputtering process, an atomiclayer deposition (ALD) process, or the like.

For example, the lower stepped pattern 210 may extend in the firstdirection. In one or more embodiments, a barrier layer covering a topsurface of the substrate 200 may be formed before the formation of thelower stepped pattern 210. The barrier layer may be formed of siliconoxide, silicon nitride, and/or silicon oxynitride.

The lower insulation layer 220 may be formed on the top surface of thesubstrate 200 to cover the lower stepped pattern 210. The lowerinsulation layer 220 may be formed conformally according to a profile ofthe lower stepped pattern 210. Thus, the lower insulation layer 220 mayinclude a protrusion or a stepped portion at a portion overlapping thelower stepped pattern 210.

The lower insulation layer 220 may be formed of, for example, siliconoxide, silicon nitride, and/or silicon oxynitride by a CVD process, athermal deposition process, an ALD process, or the like.

Referring to FIGS. 5 and 6, an upper pattern layer 230 may be formed onthe lower insulation layer 220. As illustrated in FIG. 6, the upperpattern layer 230 may fully cover the lower stepped pattern 210.

In one or more example embodiments, the upper pattern layer 230 may beformed of a metal such as tungsten, copper, aluminum, titanium, ortantalum, or a nitride of the metal. In one or more embodiments, theupper pattern layer 230 may be formed by a CVD process, a sputteringprocess, or an ALD process.

Referring to FIGS. 7 and 8, a photoresist layer 240 may be formed on theupper pattern layer 230. For convenience of description, the lowerstepped pattern 210 is illustrated to be projected under the photoresistlayer 240.

In one or more embodiments, the photoresist layer 240 may include apositive photosensitive material, a polymer structure of which may bedamaged by an exposure to light to be removed by a developing process.The photoresist layer 240 may be formed by coating a photoresistcomposition through a spin coating process or a slit coating process onthe upper pattern layer 230.

A photomask for a second photo process may be placed over thephotoresist layer 240. The photomask may include a light-shieldingportion 250 crossing the lower stepped pattern 210. A remaining portionof the photomask except for the light-shielding portion 250 may bedefined as a transmitting portion.

In one or more example embodiments, the photomask for the second photoprocess may be prepared from the photomask layout illustrated withreference to FIG. 1. Accordingly, the light-shielding portion 250 may beformed substantially from the pattern region 130 of the photomasklayout, and the light-shielding portion 250 may include a recessedportion 255 corresponding to the notch portion 140 of the photomasklayout.

As illustrated in FIG. 8, the recessed portion 255 of thelight-shielding portion 250 may be formed at a boundary area in whichthe light-shielding portion 250 and the lower stepped pattern 210overlap and cross each other. For example, an intersection region havinga quadrangle shape may be defined by the light-shielding portion 250 andthe lower stepped pattern 210, and the recessed portion 255 may beformed at each vertex of the intersection region. In one or moreembodiments, the recessed portion 255 may partially overlap the lowerstepped pattern 210.

In one or more embodiments, a plurality of the lower stepped patterns210 may be formed along the second direction, and a plurality of thelight-shielding portions 250, each of which may extend in the seconddirection may be arranged along the first direction. In one or moreembodiments, the plurality of the lower stepped patterns 210 may beformed at locations of the lower stepped regions 123 of the photomasklayout illustrated in FIG. 2, the light-shielding portions 250 may beformed at locations of the pattern regions 135, and the recessedportions 255 may be formed at locations of the notch portions 145.

Thus, a plurality of the intersection regions may be defined by one ofthe light-shielding portions 250, and the recessed portions 255 of amultiple of four may be included in the one of the light-shieldingportions 250.

Referring to FIGS. 9 and 10, the second photo process may be performedutilizing the photomask.

For example, exposure and developing processes may be performed suchthat an exposed portion of the photoresist layer 240 may be removed.Accordingly, a portion of the photoresist layer 240 under thelight-shielding portion 250 may remain to form a photoresist pattern245. The upper pattern layer 230 may be partially removed using thephotoresist pattern 245 as an etching mask. Thus, an upper pattern 235extending in the second direction and crossing the lower stepped pattern210 may be formed under the photoresist pattern 245. For convenience ofdescription, the lower stepped pattern 210 is illustrated to beprojected under the lower insulation layer 220 in FIG. 10.

The upper pattern 235 may have a substantially uniform width in thefirst direction. While performing the second photo process, a diffusedreflection and/or a spreading of the photosensitive material may occurat a portion of the photoresist layer 240 overlapping the recessedportion 255 due to a stepped portion generated from the lower steppedpattern 210. However, according to example embodiments, the notchportion and the recessed portion 255 may be formed in the photomasklayout and the photomask, respectively, in advance. Therefore, anexpansion of the photoresist pattern 245 caused by the diffusedreflection and the spreading of the photosensitive material may besuppressed so that the upper pattern 235 having a uniform line and space(LS) may be obtained.

After the second photo process, the photoresist pattern 245 may beremoved by an ashing process and/or a strip process.

In one or more embodiments, the upper pattern 235 may serve as an upperwiring, such as a data line, a source line, a drain line, etc. In one ormore embodiments, the lower stepped pattern 210 may serve as a lowerwiring, such as a scan line.

In one or more embodiments, the upper pattern 235 may serve as a gateelectrode included in a switching device or a thin film transistor (TFT)of the display device. In this case, the lower stepped pattern 210 mayserve as an active pattern of the display device, and the lowerinsulation layer 220 may serve as a gate insulation layer.

FIGS. 11 and 12 are a cross-sectional view and a top plan view,respectively, illustrating a method of forming a pattern in accordancewith a comparative example.

Referring to FIG. 11, lower stepped patterns 310 extending in the firstdirection may be formed on a substrate 300, and an upper pattern layer330 and a photoresist layer 340 covering the lower stepped patterns 310may be formed on the substrate 300. As illustrated in FIG. 4, a lowerinsulation layer (not illustrated) may be further formed before theformation of the upper pattern layer 330.

Referring to FIG. 12, the photoresist layer 340 may be patterned using aphotomask layout or a photomask that may include a pattern region or alight-shielding portion linearly extending in the second direction.

As illustrated in FIGS. 11 and 12, an inclined region 350 indicated by adashed quadrangle may be defined by portions of the upper pattern layer330 and the photoresist layer 340 adjacent to a sidewall of the lowerstepped pattern 310. A height difference of the photoresist layer 340may be generated by the inclined region 350, and thus a diffusedreflection may be caused during an exposure process. Further, aspreading or a local concentration of a photosensitive material may becaused by the height difference.

As a result, a photoresist pattern 345 formed from exposure anddeveloping processes may include a photoresist tail 347 expanded in, forexample, the first direction between the adjacent lower stepped patterns310.

When the upper pattern layer 330 is etched using the photoresist pattern345 formed by the comparative example, an upper pattern formed from theupper pattern layer 330 may have an irregular width. Additionally, theadjacent upper patterns may not be completely separated, and/or a shortcircuit may be caused therebetween.

However, according to example embodiments of the present invention asdescribed above, a notch portion or a recessed portion may be formed ina pattern region of a photomask layout or a light-shielding portion of aphotomask overlapping the inclined region 350 in consideration of thephotoresist tail. Therefore, an upper pattern having a uniform width maybe obtained, and a short circuit between the upper patterns due to thephotoresist tail may be avoided.

FIGS. 13 to 19 are cross-sectional views and top plan views illustratinga method of forming a pattern in accordance with one or more exampleembodiments. Specifically, FIGS. 13 to 16, and FIG. 18 arecross-sectional views illustrating the method of forming the pattern.FIGS. 17 and 19 are top plan views illustrating the method of formingthe pattern.

For example, FIGS. 13 to 19 illustrate a method of forming a circuitpattern or a wiring pattern utilizing the photomask layout illustratedwith reference to FIG. 1, 2, or 3. Detailed description of processesand/or materials substantially the same as or similar to thoseillustrated with reference to FIGS. 4 to 10 are omitted herein.

Referring to FIG. 13, a process substantially the same as or similar tothat illustrated with reference to FIG. 4 may be performed.

Accordingly, the lower stepped pattern 210 may be formed on a substrate200, and the lower insulation layer 220 covering the lower steppedpattern 210 may be formed.

Referring to FIG. 14, the lower insulation layer 220 may be partiallyetched to form a contact hole 225 through which a top surface of thelower stepped pattern 210 may be partially exposed.

Referring to FIG. 15, a process substantially the same as or similar tothat illustrated with reference to FIGS. 5 and 6 may be performed. Forexample, an upper pattern layer 260 sufficiently filling the contacthole 225 may be formed on the lower insulation layer 220, and aphotoresist layer 270 may be formed on the upper pattern layer 260. Theupper pattern layer 260 may be in contact with the top surface of thelower stepped pattern 210 exposed through the contact hole 225.

Referring to FIGS. 16 and 17, a photomask including a light-shieldingportion 280 may be placed over the photoresist layer 270. Forconvenience of description, the lower stepped pattern 210 is illustratedto be projected under the photoresist layer 270.

The photomask may be prepared from the photomask layout illustrated withreference to FIG. 3. In this case, the lower stepped pattern 210 may beformed on a portion of the substrate 200 corresponding to the secondlower stepped region 127 illustrated in FIG. 3.

The light-shielding portion 280 may partially overlap the lower steppedpattern 210, and may extend in the second direction. The light-shieldingportion 280 may include a recessed portion 285 formed at a boundary areain which the light-shielding portion 280 and the lower stepped pattern210 cross each other. The recessed portion 285 may correspond to thesecond notch portion 165 of FIG. 3.

Referring to FIGS. 18 and 19, processes substantially the same as orsimilar to those illustrated with reference to FIGS. 9 and 10 may beperformed.

Accordingly, a photo process may be performed using the photomask thatmay include the light-shielding portion 280 such that the photoresistlayer 270 may be partially removed to form a photoresist pattern. Theupper pattern layer 260 may be patterned using the photoresist patternas an etching mask. Thus, an upper pattern 265 extending in the seconddirection, and crossing and overlapping the lower stepped pattern 210may be formed.

The upper pattern 265 may be formed in the contact hole 225, and mayinclude a contact portion 267 which makes contact with the lower steppedpattern 210.

The photoresist pattern may be removed by an ashing process and/or astrip process after the formation of the upper pattern 265.

As described above, the light-shielding portion 280 may be formed from aphotomask layout including a notch portion to include the recessedportion 285 at a portion adjacent to an inclined region created by thelower stepped pattern 210. Therefore, a photoresist tail caused by theinclined region may be prevented or substantially prevented, and theupper pattern 265 obtained by the photo process may have a uniformwidth.

In one or more embodiments, the lower stepped pattern 210 may serve asan active pattern of a display device. In this case, the upper pattern265 may serve as a source wiring or a drain wiring, and the contactportion 267 may serve as a source contact or a drain contact.

In one or more embodiments, the lower stepped pattern 210 may serve as aconductive pad, such as a data pad or a signal pad. In this case, theupper pattern 265 may serve as an upper wiring electrically connected tothe conductive pad.

According to example embodiments of the present inventive concepts, aphotomask layout may include a pattern region in which a notch portionmay be formed at a boundary area crossing a lower stepped region.Accordingly, an irregular pattern formation caused by a diffusedreflection or a photoresist tail may be prevented or substantiallyprevented. The photomask layout and methods of forming patterns may beimplemented for formations of various structures included in a displaydevice or a semiconductor device.

The foregoing is illustrative of some example embodiments and is not tobe construed as limiting thereof. Although a few example embodimentshave been described, those skilled in the art will readily appreciatethat many modifications are possible in the example embodiments withoutmaterially departing from the novel teachings and advantages of thepresent inventive concept. Accordingly, all such modifications areintended to be included within the spirit and scope of the presentinventive concept as defined in the claims and equivalents thereof.Therefore, it is to be understood that the foregoing is illustrative ofvarious example embodiments and is not to be construed as limited to thespecific example embodiments disclosed, and that modifications to thedisclosed example embodiments, as well as other example embodiments, areintended to be included within the spirit and scope of the appendedclaims and equivalents thereof.

What is claimed is:
 1. A method of forming a pattern, the methodcomprising: forming a lower stepped pattern on a substrate such that asidewall of the lower stepped pattern extends in a lengthwise directionof the lower stepped pattern; forming an upper pattern layer on thesubstrate, the upper pattern layer covering the lower stepped pattern;forming a photoresist layer on the upper pattern layer; partiallyremoving the photoresist layer using a photomask to form a photoresistpattern, the photomask including a light-shielding portion that at leastpartially crosses the lower stepped pattern and includes a recessedportion that is recessed toward the lengthwise direction of the lowerstepped pattern; and partially removing the upper pattern layer usingthe photoresist pattern to form an upper pattern, wherein an inclinedregion is defined by the sidewall of the lower stepped pattern, and therecessed portion at least partially overlaps a portion under which theinclined region is located.
 2. A method of forming a pattern, the methodcomprising: forming a lower stepped pattern on a substrate such that asidewall of the lower stepped pattern extends in a lengthwise directionof the lower stepped pattern; forming an upper pattern layer on thesubstrate, the upper pattern layer covering the lower stepped pattern;forming a photoresist layer on the upper pattern layer; partiallyremoving the photoresist layer using a photomask to form a photoresistpattern, the photomask including a light-shielding portion that at leastpartially crosses the lower stepped pattern and includes a recessedportion that is recessed toward the lengthwise direction of the lowerstepped pattern; and partially removing the upper pattern layer usingthe photoresist pattern to form an upper pattern, wherein the recessedportion of the light-shielding portion is formed to overlap anintersection region of the light-shielding portion and the lower steppedpattern.
 3. The method of claim 2, wherein the recessed portion of thelight-shielding portion is formed to overlap a vertex of theintersection region.